Flame resistance is a characteristic of a material causing it to self-extinguish upon removal of an ignition source. A commonly used test for quantifying flame resistance is ASTM D6413 (Standard Test Method for Flame Resistance of Textiles). In a garment or similar textile-containing article, a flame-resistant fabric can dramatically reduce bodily tissue damage and increase survival rates for the wearer. Likewise, when used in structural applications, a self-extinguishing, flame-resistant composite material can undergo significantly less, perhaps even superficial, damage compared to that experienced by a comparable composite material that is not flame-resistant. Although flame-resistant composite materials have garnered significant interest for structural applications, there remains a need for further development of these systems.
A number of factors have hampered the development and implementation of flame-resistant composite materials. Although the polymer matrix of a composite material can be treated with a number of flame retardant agents suitable for imparting flame resistance (e.g., bromine, halogen compounds, metal hydroxides, metal hydrates, transition metal compounds and phosphorus-nitrogen compounds), a number of these compounds have known health hazards. An even more significant issue with these flame retardant agents is that they are known to adversely impact the structural properties of a composite material, thereby limiting range of applications in which the composite material can be used. In addition to flame retardant agents, secondary coatings and/or insulation materials can be added to a composite material to confer flame resistance. However, these protective measures add unwanted weight and bulkiness to the composite material, thereby making the composite material unsuitable for many high performance applications. Further, addition of secondary coatings and insulation materials leads to increased production costs. Although some polymer matrices have inherent flame resistance (e.g., phenolic resins), composite materials based on these polymer matrices are not typically used for structural applications due their relative low mechanical strength.
In view of the foregoing, flame-resistant composite materials that maintain mechanical properties suitable for high performance structural applications would be of substantial benefit in the art. The embodiments described herein satisfy this need and provide related advantages as well. Features described herein that confer flame resistance to a composite material can also be exploited to prepare flame-resistant articles and textiles for non-structural applications.